The following script is from "210 Days in Captivity" which aired on Nov. 10, 2013. The correspondent is Scott Pelley. Graham Messick, producer.

You don't hear much about them, but there are at least four American hostages in the hands of terrorists in Syria. They were captured in the civil war, which has killed an estimated 120,000 people and left an estimated 4 million homeless. Few know the suffering of Syria, and the suffering of the American captives, better than a 35-year-old New Yorker named Matt Schrier. That's because until his escape this summer, Schrier was among the hostages.

Tonight, he tells us about his time with the rebels fighting to take Syria -- and about his 210 days of captivity, torture and eventual salvation.

Matt Schrier: The gunfire was all day. Sniper fire all day. I mean, we were behind a wall, and you couldn't come out from that wall. If you stuck your head out from that wall, they would blow it off.

Matt Schrier is a war photographer and like most journalists, he slipped into Syria with the help of the Free Syrian Army--a moderate rebel group supported by the United States. Schrier captured these images of FSA rebels fighting the forces of the Syrian dictator Bashar al-Assad.

Scott Pelley: What were the rebels fighting for?

Matt Schrier: Freedom. One of the guy's name was Hamid Noor. After the first battle that night he was walking back, and he just looked, and he held out his hand, and the area was devastated. And he just goes, "No freedom. No freedom." And he went through his phone, and he just showed me all his friends. "Dead. Dead. Dead. Bashar. Bashar." Like that, over and over again. And that's what they all, they were all calling for, freedom.

But the men of the Free Syrian Army are not the only rebels. Many of the best-trained and ruthless fighters belong to Islamic extremist groups--rebel militias that the U.S. considers terrorists. After 18 days with the moderate Free Syrian Army, Schrier was driving out of Syria. It was New Year's Eve, and as the calendar ran out, so did his luck.

Matt Schrier: A Jeep Cherokee just cut across from the side of the road and three guys jumped out. One of 'em was cloaked completely in black, you know, like the guys in the movies -- scarf around his face, AK-47 in his hand, and he took me out, put me in the back seat of the Cherokee and he put the barrel of the gun to the side of my head.

Scott Pelley: And you thought what?

Matt Schrier: I thought, you know, my life just changed.

Changed by Jabhat al-Nusra, a rebel group in league with al Qaeda, bent on turning Syria into an extremist Islamic state. Its fighters are notorious for suicide attacks, kidnappings, and executions.

Scott Pelley: What did it mean to you that you were with Jabhat al-Nusra?

Matt Schrier: Anything could happen.

Scott Pelley: Had you seen videos of them executing prisoners?

Matt Schrier: Yeah.

Scott Pelley: Did you think that was going to happen to you?

Matt Schrier: I thought there was a good chance, yeah.

They threw Schrier in with other prisoners in what had been a children's hospital.

Matt Schrier: All I knew is that people were getting tortured. Because my second day there, that's when I started hearing people screaming. And you'd hear-- you'd hear, whap-- (CLAPPING). And they enjoy it. One of them said, "It gets me closer to God."

Scott Pelley: Torturing people?

Matt Schrier: Yeah.

He told us the chief of torture was a man named "Kawa."

Matt Schrier: He had this voice, this high pitched squeaky voice. And you can hear him interrogating people and -- zzz, zzzz, zzzz -- like, he used electricity. And-- you know, so in between whacks he hung people from handcuffs on pipes. And they would just leave them hanging there. And you know, their wrists would be out to, literally, like, out to there by the time they were done.

Scott Pelley: They were torturing people with electricity?

Matt Schrier: Yeah.

His captors accused him of working for the CIA and said that he would be judged before an Islamic court. But that day never came.

Scott Pelley: How did you count the days?

Matt Schrier: I just said them every day, like five times a day. I was very hard on myself when it came to that. You know, I was very strict and disciplined.

Scott Pelley: What do you mean you said them to yourself?

Matt Schrier: Every day, "March 1st, 2013." Just like that.

Discipline, "like that," helped him endure. And so did making a connection with the younger guards. He told us that he joked with them -- taught them to fist bump -- and he learned a little Arabic along the way. After 21 days, one jailer named Mohammed moved him to a cell where another prisoner was lying on the floor.

Matt Schrier: And this guy shoots up and his beard's out to here, and he's dirty. And he's talking to Mohammed in Arabic like, da-da-da. And Mohammed's just like, "Ameriki, Ameriki, like you." And I was like, "What are you talking about?" I didn't believe him, 'cause the guy was speaking Arabic, you know? And he looked like he had the beard and everything. And I looked and I was just like, "Oh my God, he is an American." It was a curveball. Like, I didn't expect this at all. You know, like one of the first things I said is, like, "Oh my God, they're collecting us."

The "collection" is made up of at least four Americans. The families of two of them don't want us to use their names because they believe that would make it harder to negotiate their release. Journalists Austin Tice and James Foley's families asked us to show you their pictures, to remind people that their loved ones are missing.

After holding Schrier for 33 days, Jabhat al-Nusra decided to kidnap his identity too. He told us that masked men, speaking English with no accent, forced him to give up his passwords. To throw people off his trail, they sent this email to his mother: "sorry but I have no internet and no time...I'm doing a lot of amazing photos hear." Yes, they spelled "here" h-e-a-r. If spelling was a challenge, his captors showed talent with numbers--the numbers on his credit cards.

Scott Pelley: What did it come to by the time they maxed out your credit cards?

Matt Schrier: About 17-grand.

After 37 days in the basement of the children's hospital in the city of Aleppo, Schrier says one of his jailers noticed gouges in the door of his cell. They accused him of trying to escape and made certain he would never try again.

Matt Schrier: And there were like 10 guys with masks in dressed all in black. And then they brought me down and sat me down. They put the tire on me, and they flipped me over. And there was a guy in charge, said, "Give him 115." They started whacking my feet.

Scott Pelley: How was it that they used a tire to tie you up?

Matt Schrier: They put your legs -- they make ya sit like this and then they put it over your knees--

Scott Pelley: Like a car tire?

Matt Schrier: Yeah. And then they'll take a stick and they'll wedge it on top, so--

Scott Pelley: So now it's locked over--

Matt Schrier: --it's locked into place, you can't bend your legs. And then they flip ya over, you got your feet in the air and you can't move 'em, you can't do anything.

Scott Pelley: And they start beating your feet?

Matt Schrier: Yeah.

Scott Pelley: The bottoms of your feet?

Matt Schrier: Yeah.

Scott Pelley: With what?

Matt Schrier: It's a cable. I thought it was a nightstick, that's about how thick it was.

Scott Pelley: So they said, "Okay, give him 15"?

Matt Schrier: One fifteen. One hundred fifteen.

Scott Pelley: So what is that like?

Matt Schrier: It hurts, obviously and, I mean, it sounds ridiculous, but one thing you just gotta remember is you can't curse.

Scott Pelley: Because of their religious fanaticism, no cursing--

Matt Schrier: Don't curse and just keep yellin' out, you know, "God-- God help me, God this, God that," 'cause ya know, they can relate to that. So they picked me up and they just, one on each side, dragged me back to the room and then they opened the door and the guy put his face next to me. And he said, in Arabic, he said, "Have you heard of Guantanamo Bay?"

In his first 100 days, Schrier says he was moved to new prisons repeatedly and every move was dangerous.

Matt Schrier: They wear suicide belts in case somebody tries to take their prisoners, when they move ya, they bring all their muscle.

Which the Jabhat al-Nusra rebels needed when they ran into a unit from the U.S.- supported Free Syrian Army. Schrier witnessed the anarchy that Syria has become--rebel groups of different agendas, fighting each other.

Matt Schrier: And within a couple minutes of us pulling up, we heard gunshots go off. And then they were going off constantly. And the drivers got out, ran and the suicide bombers came out. And they surrounded, you know, we saw -- there were two that I know of. You know, Mohammad had one on, there was another guy about 30 feet away and he was just standing there like this.

Scott Pelley: With his fingers on the detonators?

Matt Schrier: Yeah, and just his body language, he was ready to-- he was ready to go.

With those Arabic shouts of 'God is great,' Schrier told us he was delivered to an even worse prison, where he was shocked with a Taser, beaten and starved. As the months went by, there would be six prisons in all. And when he reached the last one, he was thrown into yet another basement cell. But in this one, there was something different near the ceiling.

Matt Schrier: In like five minutes I noticed the window, had wires all across the outside. Not thin wires. They were thick. And they were concreted into the foundation of the building. But once upon a time somebody must have broken in, because the last window, the wires didn't match up.

He spent weeks looking at the wires, but not touching -- not after being tortured for those gouges in the door.

Matt Schrier: And I would stare at it. And I figured it out. Horizontally they had three wires crossed. But they only welded it on one side. So I said, "If I take out the verticals I could bend 'em and take 'em out one at a time. Then I can bend the welded pieces back 'cause they weren't welded on both sides.

Schrier waited for the holy month of Ramadan when the faithful fast. He expected his guards would be sleeping through the day. On July 29th, his 210th day in captivity, he went at the window.

Matt Schrier: I put both my head and then both arms through first, you know? And I Supermanned out. I squirmed a little bit which made a lot of noise. And I got stuck around my waist 'cause my pants. I was wearing my pants. So I reached in, I unbuckled my pants. And as soon as I unbuttoned 'em, I just slid right out. And within five minutes I was walking through the streets of Aleppo, free.

This is what Matt Schrier looked like after seven months of captivity. But his ordeal wasn't quite over. Armed with only the Arabic he'd managed to pick up in prison, he walked through the bombed out streets of Aleppo, looking for the U.S.-backed rebels from the Free Syrian Army.

Matt Schrier: And I went up to one guy who was in a truck, sleeping. And I said, I ran up to him. I learned the Arabic that I needed to know. I said, "Help me. Help me. Kidnapped by criminals." And he goes, "(makes noise)." That means "no" in the Arab world. And he just closed his eyes like, "I didn't see nothin'." So I was like, "Great." So I start zig-zagging. It's like alleys. The city's like alleys. And I got to a main road. And I saw an old man. I did the same thing. I said [Arabic language] That means, "Help me." And he goes, "No." And by now people are wakin' up. I got to one point I turned and there was a guy s-- with his back to me with an AK and I just turned around and walked the other direction. Zig zag, zig zag, zig zag. So I saw three guys on the corner. And I walked up to 'em and I was like-- in Arabic I said, "Where's the Free Syrian Army?"

Turned out, just around the corner. They took him to the Turkish border. And he called the U.S. embassy.

Matt Schrier: They called my mother. I can speak to my mother. I spoke to my sister. Two days later they put me on a plane to JFK.

Scott Pelley: What'd you tell your mom?

Matt Schrier: Sorry. I'm sorry. I'm OK. You know, seven months is a long time to just disappear in the most dangerous country in the world.